Propeller and method of making same



y 14, 1929- T. A. DICKS 1,713,500

PROPELLER AND METHOD OF MAKING SAME Filed J 9 1928 ll/11111111111] i7 NVE R) Ham Dicks).

ATTORNEYS.

Patented May 14,1929.

' UNITED STATES PATENT OFFICE.

THOMAQ A. DICKS, OF PITTSBURGH, YENNSYLVANIA, ASSIGNOR, B Y MESNEASSIGN- MENTS, TO PITTSBURGH SCREW & BOLT COMPANY,.OF PITTSBURGH,PENNSYL- VAN IA, A CORPORATION OF PENNSYLVANIA.

PBOPELLER AND METHOD OF MAKING SAME.

Application filed January 9, 1928. Serial No. 245,596. 7

This invention relates to air craft propellers and more particularly tothe construction and method of making hollow blades for such propellers.

Many and varioustforms of hollow metal propellers for use in connectionwith aircraft, have beenproposed and patented, but an object of myinvention is to produce a hollow metal propeller blade that is superiorto any with which I am familiar.

Some of the prior hollow metal propellers are of complicated structure,others are of more or less simple structure, but employ folded or lappededges; in others the plates constituting the hollow structure are sounited that the uncture of the plates is located in the leading edge, orthe leading edge is formed by the welding metal employed in uniting theplates. The-objections to all such structures are obvious, and an objectof my invention is to produce a light, rigid, durable propeller blade ofsimple structure, which'is relatively simple and cheap to manufacture,and which overcomes objection to propellers heretofore proposed andknown to me.

A further object of-this, invention isto provide a method of making apropeller blade, from two rolled blanks, and in which the leading edgeof the blade is formed as an integral art of one of the rolled blanks,but in which iiipped and folded edges areavoided.

Another object of this invention isto provide a method of making apropeller blade from two rolled metal blanks joined tobether by welding,and in which the weldv is so formed and located that it not only-doesnot detract from the strength and durability of the blade but adds toits effectiveness.

Still another object of this invention is the production of a hollowmetal propeller blade which is formed from rolled metal lates, and

which is of such strength and rigidity as to avoid the necessity ofemploying internal stiffening or strengthening braces or .webs. exceptin connection with blades of unusual size.

A further'object is to provide a new and improved means for and methodof stiffening hollow metal propeller blades.

In the drawings, Figure 1 is a view in elevation of a blade embodyingstructural features forming a part of my invention and constructed inaccordance with the method of manufacture forming a part of myinvention. Flg. 21s an enlarged fragmentary view partially in sectionand partially in elevation of Fig. 1 and are so located relatively toeach other that they respectively show the pitch angle of the blade atstations corresponding to section lines, 5, 6, 7, 8 and 9, of Fig. 1,and

Fig. 10 is a view similar to Fig. 7 showing the modified blade of Figs.2 and 4.

The blade herein illustrated as an embodiment of my invention, iscohstructed from two rolled metal blanks, welded together and which areso formed that the leading and trailing edges of the blade constitute apart of one of the blanks, but without the necessity of folding orlapping the blank to form these edges. As shown, the shank of the bladeis formed as an integralpart of one of the blanks, and the-entirestructure, when completed, forms an integral whole which is light, butwhich possesses such rigidity and durability as to avoid the necessityof employing I internal strengthening webs or struts.

A propeller blade made in accordance with this invention consists of twoparts, the blade proper designated by A, and its tubular shank,designated by a. As shown, the blade proper is made up of an outercamber memher 6, the outer surface of which is sometimes termed thesuction face, an'inner member-f and an inlaid metal weld 3 which withthe inner member f forms the inner camber member. The outer surface ofthe inner camber member is sometimes termed the pressure face of theblade.

In the form of blade illustrated in the drawings, the outer cambermember 6 is hollow, that is, it is pressed or otherwise dished so as toform a hollow shell-like member as shown in Figs. 5 to 9 inclusive. Atone end it merges into the tubular shank a, shown in Figs. 1, 2 and 3.In the blade illustrated, the shell-like camber member e and the tubularshank a are pressed from one and the same rolled metal blank. The innermember 7, which is relatively fiat, is ressed from another rolled metalblank an the inlaid metal weld 3, of appreciable width at its outer orexposed surface, as shown in the drawings,- forms, with the inner memberf, the so-called pressure face of the blade.

In the pressing operation which shapes an outer camber member such asshown in the drawings, that portion of the blank, from which the tubularshank a is fashioned, is

pressed into the form of a trough and, by one or more subsequentoperations the shank is finished into tubular form with a jointextending longitudinally thereof, as shown at 1 in Figures 1, 2 and 3 ofthe drawings.

One of the features of my invention resides in the fact that theformation of the leading and trailing edges is accomplished withoutfolding or overlapping the metal. As shown in the drawings, the leadingedge is formed as a part of the outer camber member 6 but without thenecessity of so distorting the blank, from which that member is formed,as to set up incipient cracks or objectionable strains within the metal.That portion of the trailing edge which is subjected to the greatestshock and tothe greatest. eroding action is also formed as an integralpart of the member 6, but here again, the construction is such that theformation of the trailing edge does not produce incipient cracks or setup 1 objectionable strains in the metal.

The inner member 7 is stamped or otherwise formed from a blank of metalof substantiallythe same section as the outer camber member 6. Thesemembers are tapered in thickness, being thinnest at the'tip end ofmaximum thickness at the shank end. That portion of the blank from whichthe shank is formed is preferably of uniform thickness throughout itslength.

As shown, the inner member 7 is sli htly' curved and so formed that itlies w olly 1 within the marginal edge of the hollow outer camber member6 with its outer. surface substantially flush with the marginal edge ofthat member. That portion of the marginal edge of the outer cambermember 6, forming the leading edge of the blade, terminates in a lip,which as shown in Figs. 5 to 9 inclusive,

shields the adjacent edge of the inner member f, and the inlaid metalweld 3 which unites the members-e and f.

As shown in these figures of the drawings, the lip completes the leadingedge of the blade and is, therefore, tapered transversely of the bladeto provide the desired external curvature, so that it in effectterminates in a relatively sharp edge, which, as hereinafter noted, isbacked up and reinforced by the inlaid metal employed in producing theweld.

In the embodiment illustrated, the blank forming the inner member 7 isscarfed or beveled around its entire outer edge and with the edge of'themember 0 provides a more or less V-shaped trough or channel whichextends entirely around the member f. 1

:lhe welding operation is soperformed that blade proper.

the inner camber member of the blade is completed by the inlaid weldingmetal which, as shown in the drawings, forms a marginal surface ofsubstantial width between the superficial edges of the members 6 and f.With this arrangement thesetwo members are effectively and rigidlysecured together and in addition, the inlaid welding metal contributesto the effectiveness of the blade, by forming is such that throughoutthe major portion of the length of the blade, the weld and the inlaidmetal is, in the main, subjected to compression, as distinguished fromother strains, with the effect that the resultant strain on the weld andthe inlaid metal, is such as can be readily resisted during the normaloperation of the blade. All these features contribute to the durability,rigidity and reliability of the blade:

A blade embodying my invention may be made of any desired and approvedcontour and the 1 shank a may be formed from the blank employed inmaking the member 6. It will also be apparent that the contour of theshank may be varied, to co-operate with any approved form of hub orblade mountingmeans, solong as it isof such form to contribute to thestrength and rigidity of the- As shown, the shank a is provided withshoulders b and grooves afwhich may be formed in whole or in part duringthe pressing operation and which may be employed in connection with anysuitable means for securingthe blade in place on the hub.

the inlaid metal employed in making the same,

As illustrated, the adjacent edges of the shank are secured together byan inlaid metal weld such as heretofore described, and which extendslongitudinally of the shank'along the joint 1, and is, therefore, notsubjected to objectionable strains, ,during the normal operation of theblade. The adjacent edges of the shank are preferably scarfed orbeveled, as shown, so as to provide a suitable groove for the receptionof the inlaid metal employed in making the weld. 1

While the *blade heretofore -rdescribed is exceptio'nall strong and"rigid, the occasion may arise, or example, in connection with largeblades for further increasing ,the strength of the blade by means of aninternal rib. Where an internal rib is desired or 130 ployed.

I deemed necessary I prefer to employ a web or rib such as illustratedin the drawings. As shown, a single centrally located and longitudinallyextending web or rib g is cm- This rib preferably v extends throughoutthe entire length of the blade proper and is welded to the inner face ofthe hollow camber member 6 prior to locating the member f in placethereon. In Figs. 1 and 5 to 9, inclusive, I have illustrated the rib gand the preferred method of securing it to the member f. The rib g ispreferably tapered both in width and thickness from the shank end towardthe tip end of the blade,

and is so formed that its outer edge contacts with the membersubstantially throughout' the length of the member 6. As shown,

a series of spaced holes are bored or otherwise formed throughoutthelength of the member f and along the line of the rib g. As illustratedin Figs. 6 and 8, these holes are preferably countersunk or so formedthat they decrease in cross sectional area from the surface of member 7inwardly. The inner end of each hole should, however, be of a diametersubstantially equal to the thickness of the web. The web is then securedto the member f by an inlaid metal welding at each hole 4 in the member7. After each weld is completed, the excess of weld metal is ground offor otherwise removed so that the surface of the welding metal is flushwith the surface of the inner member 7. a The method of commerciallymanufacturing blades of this character may be carried forward as followsThe blanks, from which the members e and f are formed, may be-ro1led insuch manner as to provide the proper taper or the taper may besubsequently provided. The blanks are then cut (preferably stamped) to arudi mentary shape and this cutting or stamping operation is preferably,though not necessarily, preliminary to the subsequ'ent'pressingoperations in which the two members are given the desired and necessarycontour. These preliminary operations include the scarfing or bevelingof the edges of the members e and f. The member fis then placed inposition, with relation to the member 6, and

the welding operation, heretofore described,

is performed. As previously stated, the scarfing of the edges of one orboth of the blade members provides a groove for the reception of theinlaid metal employed in the welding operation. This welding operationmay be carried forward by the usual procedure in which the inlaid metalis deposited within the grooves formed for its reception and it ispreferable to employ sufficient metal to ovcrfill these grooves.

\Vhcre a blade is formed, as illustrated in the drawings, it isdesirable to weld together the scarfed edges of the shank a priorwelding operation is completed theexcess weld-ing metal or overfill isremoved, preferably by grinding, and the entire-surface of the completedblade may then be polished or otherwise treated for giving it thedesired surface finish. It is also apparent, that any necessarymachining operations may be performed after the welding operation.

The steps necessary for finishing the'surface of the blade will dependsomewhat upon the kind of metal employed and the finish desired. If aferrous alloy relatively high in chromium and nickel (such as one havingin the neighborhood of 18% chromium and 8% nickel) is used, the portionof the blade formed by the members 6 and f as well as the inlaid weldingmetal (if the same alloy is used for making the weld), may be given ahigh and lasting polishby ordinary grinding and polishing operations.

By carrying out the steps above outlined, I am able to construct arelatively light yet rigid and strong hollow ropeller blade which iscapable of meetii a l of the tests to which such blades are su jected.

- Having thus described my invention, what I claim is g 1. met-bod ofmanufacturing an aircraft propeller. blade which consists in shapingfrom relatively thin metal a hollow member constituting the outer cambermember and the leading edge of the blade, shaping from relativelythi'nmetal a relatively flat blank constituting a portion of the inner cambermember of the blade'of less area than the opening defined by the edge ofthe hollow member, depositing a margin of welding metal of substantialwidth around the edge of said blank to unite said blank and said hollowmember and to reinforce the portions of .said hollow member constitutingthe leading edge of the blade, and then finishing the surface 'of themetal so deposited, to'coinplete the inner camber member of the blade.

2. A method of manufacturing an aircraft propeller blade, which consistsin shaping from relativel thin metal a hollow member constituting tieouter camber member and the leading edge of the blade, shaping fromrelatively thin metal a blank constituting a substantial portion of theinner camber member of the blade, depositing a margin of welding metalof appreciable width'around the edge of said blank to reinforce theportions of said hollow member constituting the leading edge and thetrailing edge of the blade and to unite said hollow member and saidblank, and then in finishing the surface of the metal so deposited tocomplete the inner camber member of the blade.

3. A method of manufacturing an aircraft propeller blade, which consistsin shaping from relativel thin metal a hollow member constituting tieouter camber member and the leading edge of the blade, shaping fromrelatively thin metal a blank having a scarfed edge and constituting asubstantial portion of the inner camber member of the blade, but of lessarea than the opening defined by the edge of said hollow member, fittingsaid blank in place within the opening of the hollow member, depositinga margin of welding metal of appreciable width between the scarfed edgeof said blank and the adjacent edge of said hollow member to reinforcethe edge of the hollow member and to unite said ber of theblade,depositing welding metal around the edge of said blank-to unitesaidblank andsaid member and to reinforce the portions of said hollowmember constituting the leading and trailing edges of the blade,

- and finishing the surface of the metal so depositedto complete theinner camber member of the blade.

. A method of manufacturing anaircraft propeller blade, which consistsin pressingfrom relatively thin metal a hollow member constitutingtheoutercamber member, the leading edge and the shank portion of the blade,pressing from relatively thin metal a blank constituting a substantialportion of the inner camber member but of less area than the openingdefined by the edge of the hol low member, uniting the'edges of theshank portion, depositing a margin of appreciable width of welding metalaroundthe edge of said blank to unite said blank and said mem-- her andto reinforce the leading edge of the blade and the portion of saidhollow member constituting the trailing edge of the blade,

and finishing the surface of the'metal so de-- gsited to complete theinner camber memr of the blade.

I '6. A method of manufacturing an aircraft ropeller blade, whichconsists in pressing rom sheet metal a hollow member constituting theouter camber member, the leading edge and the shank portion of theblade, pressing from sheet metal a blank constituting a substantialortion of the inner cambar member of the lads, butjof less dimensionsthan the opening defined by the edge of said hollow member, securingalongitudinal- 1y extending rib to the inner face of said hol- 7. Ahollow blade for aircraft propellers,

comprising two rolled metal blanks," one shaped to formthe outer cambermember and the other shaped to form an inner member and lying whollywithin the confines of said outer camber member throughout the effectivelength of the blade and secured.

thereto solely by means of an inlaid metal weld which lies wholly withinthe pressure face of the blade and behind the leading edge thereofthroughout the effective length of the blade and which with said innermember constitutes substantially the; entire pressure face of the blade.

8. A hollow blade for aircraft propellers,

comprising two longitudinally tapered metal blanks, one shaped to formthe outer camber member of the blade and the other shaped to form aninner member of the blade and lyin wholly within the confines of saidouter cam er member throlughout the effective length of the blade, andan inlaid metal weld uniting said inner and outer'members, lying whollywithin the. pressure face of the blade and behind the leadingl ed ethereof through-.

out the effective lengt o the blade and constituting an appreciableportion of the pres-. sure face of the blade.

9. A hollow blade for aircraft propellers,

comprising two rolled metal. blanks having a shank forming portion as anintegral part of at least one of said sections, one of said sectionsconstituting the outer camber member of the blade and the otherconstituting an inner member lying wholly within the lateral edges ofsaid outer camber member throughout the effective length of the bladeand secured thereto solely by an inlaid metal weld which lieswhollywithin the pressure face of the blade and behind thel eading edgethereof. a 1

10. A hollow blade for aircraft propellers, comprising two rolledlonigitudinally' tapered metal blanks, one shape camber member and atubular shank, and the other shaped to forin an inner member lyingwholly within the bounding edges of said to form an outer 11. Ahollowblade for aircraft propellers, comprising two longitudinally taperedmetal blanks, one shaped to form the contour and pitch angles of theouter camber member and the leading and trailing edges of the blade,

and the other shaped to form an inner meminlaid metal weld constitutingthe pressure face of the blade.

12. A hollow blade for aircraft propellers,

comprising a metal blank constituting the outer camber member and theleading edge of the blade, a second metal blank constituting asubstantial portion of the inner camber member of the blade, aninlaid'metalweld of substantial width surrounding said last mentionedblank, lying w holly within the pressure face of the blade and behindthe leading edge thereof, and reinforcing the leading edge of the bladeand uniting said blanks.

13. A hollow blade for aircraft propellers, comprising a relatively:thin metal blank of decreasing thickness from the shank towards the tipend of the blade and constituting the outer camber member and theleading edge of the blade, at second relatively thin metal blankdecreasing in thickness from the shank towards the tip end of the bladeand constituting a substantial portion of the inner camber member of theblade, a marginal band of inlaid welding metal surrounding said secondblank and uniting said blanks and lying wholly within the pressure faceof the blade and behind the leading edge thereof and forming anappreciable portion of the pressure face of the blade.

14. A hollow bladefor aircraft propellers, comprising a relatively thinmetal blank of decreasing thickness from the shank towards the tip endof the blade and constituting the outer camber member and the leadingedge of the blade, a second relatively thin metal blank decreasing inthickness from the shank towards the tip end of the blade andconstituting a substantial portion of the inner camber member of theblade, a marginal band of inlaid welding metal surrounding said secondblank and uniting said blanks and lying wholly within the pressure faceof the blade and behind the leading edge thereof and forming anappreciable portion of the pressure face of the blade, and a centrallylocated longitudinally extending rib within the blade and secured tosaid blanks.

In testimony whereof, I have signed my name to this specification.

THOMAS A. DICKS.

